This paper explores the issue of native language (L1) use in adult English-as-a-second-language (ESL) classes, re-examining the belief that use of the students' L1 is detrimental to target language learning. We discuss research that (a) documents language use in several adult ESL classes in the U.S.-Mexico Borderlands, and (b) presents survey results regarding L1 use in adult ESL classes. The findings indicate that although L1 use was uncommon in the classes observed, the first language can serve as an important pedagogical tool. (Contains 1 table and 1 endnote.)